I'm using my MBP mostly when I'm on the road, not for the "serious" stuff, so I can't verify, but this sounds nasty. Just to make sure I'd lodge the error via the official bug reporting system:
Maybe some other users can confirm. In the meantime you may wish to try and save the file to another drive or attempt the usual "fixes" like excluding the save folder from Spotlight search and Time Capsule (if you use it)...
Upon closer inspection, it seems the FTP option was checked off in the format options, with no server listed. That may account for the first error message (not sure why that didn't fail as soon as I hit the render button though). I still got that second error message, but this time it was after the spot completed rendering and the file was intact and usable.
I will attempt it with a few different projects and see if I can duplicate the results.